Thermostatic control means for gas burners



Oct. 19, 19 A. J. HILDENBRANDT 3,212,712

THERMOSTATIC CQNTROL MEANS FOR GAS BURNERS 2 Sheets-Sheet 1 OriginalFiled June 25, 1962 No. 5 m]; no

n INVENTOR l5 AUGUST J. HILDENBRANDT.

ATTORNEY Oct- 1 1965 A. J. HILDENBRANDT THERMOSTATIC CONTROL MEANS FORGAS BURNERS 2 Sheets-Sheet 2 Original Filed June 25, 1962 F I I l I I lI L Y mm T. N o N A W E m N N 1 w "fl 1w Z T. S U G U AY United StatesPatent ()fiice 3,212,712 Patented Oct. 19, 1965 3,212,712 THERMOSTATICCONTROL MEANS FOR GAS BURNERS August .1. Hildenbrandt, Scotch Plains,N..I., assignor to The Wilcolator Company, Elizabeth, N.J., acorporation of Delaware Continuation of abandoned application Ser. No.204,740, June 25, 1962. This application July 24, 1964, Ser. No. 387,267

2 Claims. (Cl. 23699) This application is a continuation of myapplication Serial Number 204,740 filed June 25, 1962, now abandoned.

This invention relates generally to thermostatic regulation of the flowof fuel gas to burners of ovens, cooking ranges and the like, by burnercontrol systems of the type including a thermally actuated cycling valvefor operating the burner in an off and on manner to maintain a selectedtemperature. More particularly, the invention is directed toimprovements in a temperature selecting control valve means whichpermits unrestricted fiow of fuel gas to the cycling valve during normaloperation and yet permits the gas supply to be shut off in the usualmanner in the event of failure of the thermostatic or cycling valves.

In some burner cycling systems the cycling valves is connected directlybetween the gas source and the main burner and is actuated betweenopened and closing positions in response to presence or absence of aflame at a control pilot burner which is thermostatically controlled inaccordance with the oven or stove temperature by a manually adjustablethermostatic control valve. This form of control is considered dangerousin that, in the event of failure of the cycling valve to close, or inthe event of failure of the thermostatic portion of the control valve,the supply of gas to the burner cannot be shut ofi in the usual way byturning the thermostatic control valve knob to the off position.

In other burner cycling systems it has been the practice to avoid thisdanger by causing the gas to flow in series from the supply through anon-off valve, then through a thermostatic valve to both the main burnercycling valve and the control pilot burner. Because the gas flowing tothe main burner must first pass through the thermostatic valve, arelatively large thermostatic valve is required and the flow of gas tothe main burner is diminished as the oven or range approaches theselected temperature.

With the foregoing in mind, it is a principal object of this inventionto provide a novel burner cycling system and control valve device whichovercomes all of the foregoing disadvantages in a particularly simpleyet reliable manner.

Another object of this invention is the provision of an improved controlValve device for use in a system including a cycling valve forcontrolling the flow of gas to a main burner in response to presence orabsence of a flame at a control burner, the improved control valvedevice having a manually operated shut-off valve, disposed between thesource and the cycling valve, and a manually adjustable thermostaticvalve for controlling a flow of gas from the shut-off valve to thecontrol pilot burner without affecting the flow of gas to the cyclingvalve, yet permitting manual operation of the shut-off valve in theusual way to interrupt all gas flow in the event of a failure in anypart of the system.

As another object this invention aims to provide an improved controlvalve device of the foregoing character wherein all of the gas passesthrough a manually positionable on-off or shut-off valve, but only thegas to the control pilot burner passes through the thermostatic valve,whereby a relatively small, eflicient thermostatic valve may be employedresulting in a particularly compact, reliable, and safe valve device.

Still another object of this invention is the provision of a controlvalve device comprising a body including a chamber having an inletpassage controlled by a manually positionable valve member, a firstoutlet passage for connection with a main burner through a cyclingvalve, and a second outlet passage controlled by thermostatic valvemeans for regulating gas flow to a control pilot for actuating thecycling valve, and a single manually operable means for positioning thevalve member and adjusting the thermostatic valve means.

Other objects and advantages of this invention will become apparent fromthe following detailed description of a preferred example of a burnercycling system and control valve means embodying the invention read inconjunction with the accompanying sheets of drawings forming a part ofthis specification, and in which:

FIG. 1 is a side elevational view of a control valve de vice embodyingthis invention as part of a schematically illustrated gas burner controlsystem;

FIG. 2 is a front view of the control valve device taken along line 2-2of FIG. 1;

FIG. 3 is a longitudinal sectional view of the control valve devicetaken substantially along line 3-3 of FIG. 2 and illustrated as part ofthe control system of FIG. 1;

FIG. 4 is a sectional view taken along line 44 of FIG. 1; and

FIG. 5 is a fragmentary top view taken along line 55 of FIG. 1 with aportion broken away.

Although burner control systems and control valves embodying thisinvention may be utilized for controlling gas flow to top burners ofdomestic ranges, kilns, and the like, the invention will be describedhereinafter with reference to use in the baking oven of a domesticstove.

Referring to FIG. 1, a control valve, generally indicated at 10, formspart of a gas heating system for an oven 11 which is shown schematicallyand may be of any conventional construction, the heating systemincluding a main oven burner 12 arranged to be ignited by a standbypilot burner 13. Pilot burner 13 is provided with a constant supply offuel through pipe 14 which is connected through a screw adjustment valve15 to a gas manifold 17 forming part of the oven and which arrangementis well known in the art. Oven burner 12 is supplied with a flow of fuelfrom the manifold 17 through the control valve 10 and a thermallyactuated cycling valve 18 which is connected between valve 10 and burner12 by suitable pipes 19 and 20, respectively. The control valve 10,together with the cycling valve 18, controls the flow of gas to the ovenburner 12 in a manner described more fully hereinafter.

The cycling valve 18, which is adapted to interrupt the fiow of gas toburner 12, may be of any convenient construction well known in the artbut is preferably of the type disclosed in now abandoned patentapplication Ser. No. 109,035, filed May 10, 1961, and assigned to theassignee of this application, and to which reference may be had for amore complete description. Suffice it to say, however, that the cyclingvalve 18 is of the quick opening and closing type and is connected by acapillary tube 21 to a temperature sensing bulb 22 which is disposedover a control burner 24. The bulb 22 and tube 21 contain an expansiblefluid and communicate with an expansible, valve operating power member(not shown) for opening and closing the valve 18 in accordance with thepresence or absence, respectively, of a flame at the control pilotburner 24. The control pilot burner 24 is connected by a supply pipe 25to an outlet connection 26 of the valve device 10 which supplies gas tothe burner pilot in accordance with oven temperatures sensed by atemperature sensing bulb 28 in a manner which will become apparent asthe description proceeds.

Referring more particularly now to FIG. 3, valve comprises a valve body38, preferably formed of aluminum or other suitable metal, and having agenerally conical shaped recess 31 formed therein, the larger end of"which is closed by a cover member 32 secured to body 30 by screws 33with a suitable gasket 34 interposed therebetween. The end of body 30opposite cover member 32 is provided with a flat smooth face 36 whichserves as a seat for a rotatable valve disc 37 which is arranged torotate relative to face 36 while maintaining a gas tight seal with theareas engaged thereby. Body 39 is provided with a gas inlet passage 40,the outer end of which is connected with an internally threaded boss 17aof manifold 17 by a nipple 41 having a flange 42 secured to the valvebody 36 as by screws 43, and the inner end of which passage opens inface 36. The valve disc 37 is provided with an arcuate recess 44 facingsurface 36 and, as may be seen in FIG. 4, this recess subtends an angleof about 235. The valve disc 37 is illustrated in FIGS. 3 and 4 in an oncondition in which the recess 44 overlies the inner end of inlet passage40' and also overlies one end of an arcuate passage 47 leading fromsurface 36 directly into the chamber formed by recess 31 and covermember 32. The cover member 32 is provided with an outlet passage 48through an outlet connection 49 which is connected to pipe 19 leading tothe cycling valve 18.

A threaded bore 50 is formed in the valve body 30 at the inner, orsmaller end of recess 31 and a control pilot burner gas flow passage 51leads from the threaded bore through drilled passage ways 52 and 53 tothe outlet con- ,nection 26 which is connected to the control pilotburner supply line 25.

Gas passes from the recess or chamber 31 into the threaded bore 50 underthe control of a thermostatically operated valve means, described morefully hereinafter, for exit through passages 51, 52, 53, and supply line25 to the control pilot burner. A needle valve member 54 having a screwdriver slot 55 is threadedly engaged in passage 52 and is adapted to beadjusted to vary the flow path at the junction of passages 51 and 52 toregulate the maximum flame height at the control pilot burner 24.

The mentioned thermostatically operated valve means comprises acup-shaped valve seat member 60 threaded into threaded bore 50 andhaving a flaring end opening into the chamber for-med by recess 31 toprovide an annular valve seat 60a. The valve seat member 60 has an endwall 60b provided with openings 60c through which gas passes into thethreaded bore 50. The seat member 60 can be rotated in the threaded bore58 varying its position relative to a thermostatically positioned valvemember 62, described more fully hereinafter, by a shaft 63 connected tothe end wall 60b of the valve seat member as shown.

An expansible wafer 65 is mounted on cover member 32 and preferablycomprises two nested corrugated flexi- -ble discs 65a and 65b weldedtogether about their rims to form an expansible chamber containing arelatively small volume of an expansible fluid. The disc 65b is securedto a nipple 67 mounted in an opening in cover member 32 and having apassage communicating with the interior of the wafer 65. A capillarytube 68 has one end brazed in the nipple 67 and has its other endcommunicating with the interior of the temperature sensing bulb 28located in the oven 11. The wafer 65, tube 68, and bulb 28 are filledwith a suitable fluid, preferably liquid, which expands and contractsupon increases and decreases in temperature to cause correspondingexpansion and contraction of the wafer 65 in a manner which is wellunderstood in the art.

The disc 64a is provided with a stem 70 on which is mounted thedisc-like valve member 62 which is adapted .to be moved toward and awayfrom seat 60a by expansion and contraction of the expansible wafer 65 inresponse to temperature changes sensed by bulb 28. The valve member 62is preferably mounted on stem 70 between a bimetallic washer 71 and aspring 72 which permits limited movement of the valve member withrespect to the stem to assure proper alignment thereof with the valveseat 60a. The bimetallic washer is adapted to flex in response tochanges in temperature to vary the position of the valve member alongthe stem 70 in compensation for changes in volume of the liquid insidethe wafer 65' due to temperature changes inside the valve body. Aresilient O-ring 73 provides a seal between the valve member 62 and thestem 70.

It will be appreciated that the flow of gas from the recess 31 throughthe thermostatic valve means to the control pilot burner 24 will bedependent upon the temperature of the oven experienced by the sensingbulb 28 and by the positioning of the valve seat member 60 axially ofthe threaded .bore 50. It will also be appreciated that the valve member37 provides an on-oft control of the flow of gas from the manifold 17 toboth the main burner 12 through the cycling valve 18 and the controlpilot burner 24 through the thermostatic control valve means.

Because of the length of the arcuate recess 44, the valve member 37 maybe rotated through approximately 200 of angular movement while in a fullon condition. This range of movement permits the shaft 63 and valve seatmember 60 to be rotated to position the latter axially of threaded bore50 to select a desired oven operating temperature while effectingsimultaneous rotation of the valve member 37 from an off position to anon position by means of a single, manually operated knob 80.

Knob is drivingly connected to both the valve member 37 and the shaft 63in such a manner that both are normally operated simultaneously, yet theshaft 63 may be rotated independently by a service man for calibratingthe valve device. To this end, the inner end of the shaft 63 issupported for axial and rotatable movements by a packing washer 81secured in a recess at the bottom of the threaded bore 50 by a washer 82held in place by a rolled-over lip 83. The intenmediate portion of shaft63 extends freely through a central opening in the valve disc 37, andthe outer end is pinned in an externally threaded bushing 84 forrotation therewith. A compression spring 85 is disposed between thevalve member 37 and the bushing 84 and acts to hold the valve memberagainst face 36 and to provide a drag against rotation of the valve seatmember 60 in the threaded bore 50. The bushing 84 has a stem portionprovided with a screw driver slot 86 which permits rotation of the shaft63 for calibration purposes, and the bushing is threaded in a sleeve 87having diametrically extending ears 88. The threaded sleeve 87 isslotted to form fingers having an inward set for resiliently grippingthe bushing 84. The ears 88 are engaged in axially extending, opposedslots 89 in the side walls of a cup-shaped drive member 90 which has anend wall 91 having a central opening in which is secured asemi-cylindrical shaft 92 through which is exposed the screw driver slot86 on the stem portion of the bushing 84.

The drive member 90 is rotatably supported in a sleeve portion 93 of anannular cover member 94 which is secured by screws 95 to the valve body30. The drive member 90 comprises a radially extending flange 96disposed against the inside surface of a shoulder portion 97 of cover 94and is biased outwardly by a spring 100 acting between the valve member37 and an inner shoulder 101 of the drive member. A drive lug 102extends from the outer edge of flange 96 into engagement with a notch103 formed in the periphery of valve member 37 and causes the latter tobe rotated with the drive member. The sleeve 87 also is rotated by theears 88 in engagement with the drive member 90 and frictionally gripsthe bushing 84 so as to effect rotation of the shaft 63. Thus, the knobmay be rotated to bring the recess of valve member 37 into registrationwith both the inlet passages 40 and 47 so as to admit a supply of gas tothe recess 31, and to axially position the valve seat member 60 toselect a temperature which will be maintained in the oven 11.

Assuming the oven 11 to be cold and the knob to have been rotated in thejust mentioned manner to turn on the gas supply and to select atemperature to be maintained in the oven, gas will immediately flowthrough the outlet connection 49 to the cycling valve 18 which is in aclosed condition. Gas will also flow through the thermostatic valve seatmember 60 through passages 51, 52, and 53 through supply line 25 to thepilot burner 24 which is thereupon ignited by the standby pilot 13. Theflame of the control pilot burner 24 plays upon the temperature sensingbulb 22 connected by capillary tube 21 to the cycling valve 18, causingthe latter to quickly open and admit a flow of gas to the main burner 12which is thereupon ignited by the standby pilot burner 13.

The main burner 12 continues to burn until the temperature in the oven11 rises to the preselected temperature, at which time the liquid in thetemperature sensing bulb 23 expands sufiiciently to distend the wafer 65and seat the valve member 62 against the annular seat 60a. The supply ofgas to the control pilot burner is thereby cut oil, causing the controlpilot burner 24 to be extinguished, the bulb 22 to cool, and the cyclingvalve 18 to quickly close. The closing of valve 18 extinguishes the mainburner 12, whereupon the oven temperature begins to recede.

As the oven temperature recedes, the corresponding contraction of theliquid in bulb 28 results in contraction of the wafer 65 and movement ofthe thermostatic valve member 62 away from its seat 60a. Gas again flowsthrough the now open thermostatic valve member to the control pilotburner 24 which is re-ignited by the standby pilot 13 so as to heat bulb22 and cause opening of cycling valve 18 and re-ignition of the mainburner 12. The foregoing sequence of events is repeated, with the mainburner being cycled between on and off conditions in accordance with thepresence or absence of a flame at the control pilot burner 24 asregulated by the thermostatic valve.

From the foregoing detailed description of a burner cycling system andcontrol valve means embodying this invention, it will be appreciatedthat there has been provided thereby a novel valve means which permitsthe supply of gas to the main burner and control pilot burner to be shutoff, in the event of cycling or thermostatic valve failure, by merelyturning the control knob to its off position in the usual manner. Itwill also be appreciated that only the gas flowing to the control pilotburner is passed through the thermostatic valve means so that a smalland reliable thermostatic valve means may be utilized without affectingthe gas supply to the main burner.

Although the invention has been described with detailed reference to aspecific burner cycling system and control valve means embodying theinvention, it will be understood that the invention is not limitedthereto, but rather the invention includes all those changes,modifications, substitutions, and uses as are reasonably embraced by thescope of the claims hereof.

Having described my invention, I claim:

1. In a thermostatic valve for controlling the flow of gas to a burner,a valve body with walls forming a chamber therein, one end wall of saidchamber having an opening therethrough, a thermostatically operatedvalve closure member in said chamber, a rotatable shaft closed to flowof gas therethrough and projecting through said opening in said end walland extending into said chamber, sealing means forming a gas tight sealbetween the edges of said opening through said one wall of said chamberand said shaft, said one wall having a recess therein providing a gaspassage, one end of said recess being closed by said sealing means andthe portion of said one wall surrounding said shaft, valve seat means atthe other end of said recess forming a valve seat for said valve closuremember, means connected with said shaft for adjusting thermostaticoperation of said valve closure member relative to its seat uponrotation of said shaft, said end wall of said chamber having arelatively small volume gas passage leading from adjacent said one endof said recess to the exterior of said body, said end wall of saidchamber having a main flow passage therethrough of substantially greatervolume capacity than said small volume gas passage and leading from theouter surface of said end wall into said chamber, another wall of saidchamber having a flow passage therethrough of substantially the sameflow capacity as that of said main flow passage leading from theinterior of said chamber to the exterior thereof for supplying gas to aburner, and a valve member on the exterior of said end wall and attachedto said rotatable shaft and rotatable thereby to move relative to theopening of said first mentioned relatively large volume flow passage insaid outer surface of said one end wall to control the flow of gastherethrough.

2. In a thermostatic valve for controlling the flow of gas to a burner,a valve body with walls forming a chamber therein, one end wall of saidchamber having an opening therethrough, a thermostatically operatedvalve closure member in said chamber, a rotatable shaft closed to theflow of gas therethrough and projecting through said opening in said endwall and extending into said chamber, sealing means forming a gas tightseal between the edges of said opening through said one wall of saidchamber and said shaft, said one wall having a recess therein open atone end to the interior of said chamber and the other end of said recessbeing closed by said shaft and said sealing means, a cylindrical valveseat member threaded into said open end of said recess and the outer endthereof forming a valve seat for said valve closure member, meansforming a driving connection between said shaft and said valve seatmember for adjusting the position of said valve seat relative to saidvalve closure member by rotation of said shaft, one end wall of saidchamber having a relatively small volume gas passage leading fromadjacent said other end of said recess and inwardly beyond the inner endof said valve seat member to the exterior of said body, said end wall ofsaid chamber having a main flow passage therethrough of substantiallygreater capacity than said small volme gas passage and leading from theouter surface of said end wall into said chamber, another wall of saidchamber having a gas flow passage therethrough and having a capacitysubstantially equal to that of said main flow passage and leading fromthe interior of said chamber to the exterior thereof, and a valve memberon the exterior of said end wall and attached to said rotatable shaftand rotatable thereby to move relative to the opening of said firstmentioned relatively large volume flow passage in said outer surface ofsaid end wall to control the flow of gas therethrough.

References Cited by the Examiner UNITED STATES PATENTS 1,842,335 l/32 TePas 236-68 2,153,886 4/39 Grayson 23615 3,065,913 11/62 Holzboog et al23668 FOREIGN PATENTS 803,132 9/36 France.

EDWARD J. MICHAEL, Primary Examiner.

ALDEN D. STEWART, Examiner.

1. IN A THERMOSTATIC VALVE FOR CONTROLLING THE FLOW OF GAS TO A BURNER,A VALVE BODY WITH WALLS FORMING A CHAMBER THEREIN, ONE END WALL OF SAIDCHAMBER HAVING AN OPENING THERETHROUGH, A THERMOSTICALLY OPERATED VALVECLOSURE MEMBER IN SAID CHAMBER, A ROTATABLE SHAFT CLOSED TO FLOW OF GASTHERETHROUGH AND PROJECTING THROUGH SID OPENING IN SAID END WALL ANDEXTENDING INTO SAID CHAMBER, SEALING MEANS FORMING A GAS TIGHT SEALBETWEEN THE EDGES OF SID OPENING THROUGH SID ONE WALL OF SAID CHAMBERAND SAID SHAFT, SAID ONE WALL HAVING A RECESS THEREIN PROVIDING A GASPASAGE, ONE END OF SAID RECESS BEING CLOSED BY SAID SEALING MEANS ANDTHE PORTION OF SAID ONE WALL SURROUNDING SAID SHAFT, VALVE SEAT MEANS ATTHE OTHER END OF SAID RECESS FORMING A VALVE SEAT FOR SAID VALVE CLOSUREMEMBER, MEANS CONNECTED WITH SAID SHAFT FOR ADJUSTING THERMOSTATICOPERATION OF SAID VALVE CLOSURE MEMBER RELATIVE TO ITS SEAT UPONROTATION OF SAID SHAFT, SAID END WALL OF SAID CHAMBER HAVING ARELATIVELY SMALL VOLUME GAS PASSAGE LEADING FROM ADJACENT SAID ONE ENDOF SAID RECESS TO THE INTERIOR OF SAID BODY, SAID END WALL OF SAIDCHAMBER HAVING A MAIN FLOW PASAGE THERETHROUGH OF SUBSTANTIALLY GREATERVOLUME CAPACITY THAN SAID SMALL VOLUME GAS PASSAGE AND LEADING FROM THEOUTER SURFACE OF SAID END WALL INTO SAID CHAMBER, ANOTHER WALL OF SAIDCHAMBER HAVING A FLOW PASSAGE THERETHROUGH OF SUBSTANTIALLY THE SAMEFLOW CAPACITY AS THAT OF SAID MAIN FLOW PASAGE LEADING FROM THE INTERIOROF SAID CHAMBER TO THE EXTERIOR THEREOF FOR SUPPLYING GAS TO A BURNER,AND A VALVE MEMBER ON THE EXTERIOR OF SAID END WALL AND ATTACHED TO SAIDROTATABLE SHAFT AND ROTATABLE THEREBY TO MOVE RELATIVE TO THE OPENING OFSAID FIRST MENTIONED RELATIVELY LARGE VOLUME FLOW PASSAGE IN SAID OUTERSURFACE OF SAID ONE END WALL TO CONTROL THE FLOW OF GAS THERETHROUGH.